Method of oxidizing unsaturated fatty bodies



Oct. 5, 1948. J. D. FrrzPATRlcK Erm. 2,450,858

METHOD OF OXIDIZING UNSATURATED FATTY BODIES Filed Jan. 2o, 1944' Ns N o 20mm.

INVLENTOR.

Patented` Oct. 5, '1948 METHOD F OXIDIZING UNSATURATED FATTY BODIES' J. D. Fitzpatrick and Latimer D. Myers,

Cincinnati, Ohio Application January 2o, 1944, serial No. 518,992 24 claims. (C1. 26o-406) l This invention relates to a methodof oxidizing relatively long chain unsaturated fatty bodies to provide relatively short chain saturated fatty bodies.

This type of reaction takes place when various materials, such as olive oil. cottonseed oil, soy

bean oil, tea seed oil, palm oil,.cocoanut oil, yrape v 2 produce the desired cleavage has been too great in respect tothe value of Ithe obtainable yields of the saturated short chain fatty bodies. Disruptively oxidizing each double bond requires four reactive atoms of oxygen and heretofore there has been no method of supplying such quantities of oxygenin reactive condition at a cost approseed oil, linseed oil, corn oil, and other vanimal or v vegetable oils having substantial quantities of un- ,f saturated components are treated with a cleavage producing oxidizing agent. Though the yield is less, the same general process may be applied to garbage grease, brown grease, tallow, or other fatty materials having a higher percentage of saturated components but still some percentage of unsaturated components. The' process may also be applied to the fatty acids obtained from any of the materials named, either before or after separation of the unsaturated fraction from the' rest of the materiahor may be applied to the esters of unsaturated fatty acids such as the methyl, ethyl, propyl, etc., esters, or to synthetic products which are unsaturated.

Inasmuch as the reagents utilized in this process attack the unsaturated bodies primarily at, the double bonds, the method may be applied generally for treating chemical compounds made up in whole or in part of a long chain unsaturated fatty acid radical without interfering with the saturated radicals present. For instance, tallowl may be split to provide a mixture of oleic, palmitic, and stearic acids, the oleic acid separated from the solid saturated fatty acids by pressing, and the oleic acid treated to produce shorter chain fatty acids, or, on the other hand, the tallow may be treated to split the oleic component at the double bond and splitting and separation may be performed afterward. Claims directed to the oxidation as a step in separating saturated and unsaturated fatty acids appear in our copending application Serial No. 396,752.

It has long been known that these long chain unsaturated fatty bodies could be oxidized to produce cleavage at the double or multiple bonds to provide shorter chain bodies with acid radicalsat the points of oxidation. A familiar text book example of this is the oxidation of oleic acid with potassium permanganate, ozone, or the like, into Nitric acid and adazelaic and pelargonic acids. mixtures of sodium dichromate and sulphuric acid have also been proposed as oxidizing agents.

However, there has heretofore been no feasible method of oxidizing the relatively long chain unsaturated fatty bodies because, primarily, the cost of oxidizing agents suiciently powerful to 'prlate'"for,4 l'the value 'of .the-recoverable, reaction y-pr0duci',s. i

f The problem to which this invention is directed is the provision of a process for supplying oxygen to unsaturated fattyv bodies in a form which is reactive with them to produce cleavage, which does not produce an oxidation which is too destructive to. the fatty bodies and which does not consume relatively expensive reacting materials.

On analysis, the raw material or reagent utilzed for the supply ofv oxygen, according to the present invention, is water which is electrolytically decomposed to produce hydrogen and to convert chromium sulphate into chromic and sulphuric acids which, in turn, are utilized for oxidizing the unsaturated fatty material, then again converted to the acid form for reuse. Thus, Va given solution of chromium sulphatel may be used and reused on an indefinite number of batches of fatty material with the addition of no new reagent other than water which is consumed in the process. The'by-product of the electrolytic decomposition of Water is hydrogen which may be advantageously used to treat other unsaturated fats to harden them. Thus, the process as a whole is adapted to be used for treating unsaturated fats to improve their values by hydrogenating certain fats and dsruptively oxidizing other fats, both the hydrogen and the oxygen of the decomposition being used ultimately to decrease the' unsaturation of fats.

Though it has long been known that mixtures of chromic and sulphuric acids were powerful oxidizing agents, in most cases producing a destructive oxidation of `organic materials, and though it has long been known that oxidizing agents of this character had the effect of cleaving unsaturated fatty bodies at the double bonds, still it has not been heretofore recognized that it was possible to produce an intersolution of these two bodies and water which was capable both of pro- 'viding a high yield of desirable reaction products and of being reconditioned by electrolysis at reasonable cost to permit its repeated'and continued use. Our investigation has disclosed that this process is feasible but that, of the various possible solutions of chromic and sulphuric acids, a small range only is suitable for the practice of the present invention on an economic and commercial basis.

This application is a continuation in part of our copending application Serial No. 385,740, now abandoned, in which we recommended the use of a 50 to 60% regenerated solution comprising one part chromic anhydride, two parts sulphuric acid and four parts water. The recommended solution is entirely suitable for the practice of the present invention, both from the point of view of getting a good yield and from the point of view of reconversion. At the time of filing the preferred solution disclosed in the present-` application. Such a solution when electrolyzed to convert 40 to 75% of the chromium sulphate to chromic and sulphuric acids reacts upon the unsaturated fatty material being treated .substantially like the fresh solution except. of course, that a greater quantity must be used in order to supply the requisite amount of oxygen. While the solution may be converted to any desired degree our investigation has disclosed that 40 to '15% constitutes a range which is both efficient and economical.

As disclosed in the previously filed application, the range of from 50 to 60% conversion is the preferred one. However, it must be understood that with the lower conversions greater quantities of reagent must be handled and that as the conversion progresses the eiilciency of the operation decreases, very rapidly above 50 to 60%. Thus the exact conversion suitable for any specific operation must depend upon the cost of electric current and the equipment available both for electrolysis and treatment of the fat.

The admixtures of chromium sulphate. sulphuric acid and water which may be used successfully for conversion to an oxidizing agent by electrolysis and for cleaving the fat molecules at the double bonds constitute but a small proportion of the number of such admixtures possible. The nature of the desirable and useful oxidizing solutions of our invention may be best understood by reference to the drawing, the vflgv ure of which discloses a triangular chart or graph, any point on which represents a solution composed of a certain percentage of chromium sulphate. of sulphuric acid and of water.

The composition of our preferred solution is predicated upon a 50 to 60% conversion, and at greater or lesser degrees of conversion within the range of 40 to '75% the composition of the preferred solution may shift to some extent within the prescribed limits.

It is the prerequisite of a useful solution that it can be electrolyzed economically, and that when so electrolyzed it will provide a highly active oxidizing agent which, in turn, will produce a high yield of valuable reaction products when applied to the fatty material. In the lower righthand corner of the drawing is a small parallelogram designated useful range and a, point within the parallelogram designated preferred reagent." The drawing is slightly shaded to indicate that the reagents increase in utility away 4 from the margin of the parallelogram and toward the preferred reagent.

The graph is predicated upon the composition of a spent solution inasmuch as it is the spent solution which is the starting material for each batch of fatty material treated except perhaps the first. The significance of the parallelogram is as follows:

The solution should contain at least 7% sulphuric acid, because if substantially less is used, then the oxidation proceeds so slowly that the process is not commercially feasible. This is not to say that the reaction will not take place, but that the difficulty of obtaining a reaction between the reagent and fatty material to produce a useful yield of materials is exceedingly tedious and cumbersome.

In addition, the voltages required for conversion to the oxidizing agent are quite high and thus the conversion costs are excessive. Al-

together the use of less than 7% of sulphuric acid results in the production of a reagent which is .weak and expensive.

We have found that the amount of sulphuric acid present in the spent solution which is to be used as a starting material in this process is very important from the point of view of cell voltage in the conversion process. If no sulphuric acid is present the voltage required is very high but if sulphuric acid is added the voltage drops rather rapidly until concentration of about 10% sulphuric acid in the solution is reached after which there is no further appreciable voltage drop. At a concentration of substantially 7% sulphuric acid the voltage required for conversion is down almost to minimum and the solution when converted 50 to 60% constitutes a reagent which will oxidize the fatty material with reasonable celerity.

As the percentage of sulphuric acid is increased over fifteen percent the reaction tends to accelerate to such a degree that the yields of the desirable materials and particularly the dibasic acids are reduced. We regard a concentration of substantially 20% sulphuric acid as about the upper working limit though greater amounts may be used at the cost of reduced yields and without benefit to the efilciency of the conversion. Thus a sulphuric acid concentration of between 10 and 15% provides a solution which requires a minimum voltage for conversion and which produces the highest yields of desirable materials. We regard a l2 to 13% concentration of sulphuric acid as the optimum.

The chromium sulphate concentration should be between 15 and 35%. If the concentration be less than 15% then the conversion eillciency falls off materially and the volume of solution which must be handled and kept in admixture with the fatty material being treated becomes excessive.

If the concentration of the chromium sulphate be over 35% then the solutions will not remain uid over a period of time at ordinary temperatures and cannot be safely handled for conversion. These chromium sulphate solutions have the characteristic of behaving like supersaturated solutions and solidifying after a period of time so that they will not run or pour. Great difficulty would be encountered if such a solution were being converted in electrolytlc cells and a mischance or accident, perhaps t0 the rectifier, required suspension of the operation. The solution would harden to such a degree that it would be impossible to resume the electrolysis without completely dismantling the equipment to remove vrnarily upon the equipment the solid solution.` Obviously it is highly undesirable in the operation of any plant to attempt to handle any material which on standing tends to go from a liquid to a solid.

'I'hese limits are not sharply defined as the de- I crease in desirability and eifectivenessfas we move away from the preferred solution, is gradual but the limits are those beyond which it is' fuging may be employed to accelerate this sep;`

aration, if desired.

In carrying out the reaction of breaking down A the relatively long chain unsaturated fatty bodies into relatively short chain saturated fatty bodies with a reagent of the type described, the temperature must be elevated to approximately 50 C.

to initiate rapid reaction. However, the reaction is exothermic and tends to elevate the temperature of the liquids to such a degree that cooling is usually required to keep the temperature below 95 to 100 C., which prevents an excessively violent reaction. Preferably, the reaction is permitted to progress at a controlled temperatureof between 75 C. and 90 C.

If the preferred solution is used the chemical reaction itself is almost instantaneous, and the time consumed depends upon the rate at which the raw material and reagent can be intermixed lwithout having the temperature exceed a safe limit of, say, 95 C. Otherwise expressed, the

speed of the reaction, as a practical matter, is a I function of intermixture and temperature. Thus, the time required for the reaction depends priemployed in .relation to the volume of the batch being treated. If desired, the reaction may be eil'ected by the wellknown countercurrent flow or concurrent iiow methods of producing chemical reactions.

The reagent may be added to the batch 'being treated in one ,portion but we have found it better to add the required amount of reagent in a series of quotasso that spent reagent does not dilute unspent reagent. For instance, one-third of the required amount of reagent is added to the batch being treated, and after it is spent, as indicated by the change of color of the admixture from brown to green, the reagent is settled and drawn off, after which the batch of fatty bodies is similarly treated with two additional quotasl of reagent.

The products of reaction may be separated to the desired degree for theirintended chemical purposes byk distillation, water washing or other forms of solvent separation proceeding upon the principle of differential solubilities of the'components of thetreated material in varioussolvents. The products of the reaction necessarily differ depending upon the nature of the starting material but, for the purpose of disclosing one process of separating these components oleic acid is taken as a typical example.

From the treatment of oleic' acid one obtains azelaic acid, pelargonic. acid, and shorter chain 75 of moved from the fatty acids such as palmitic, lmyristic, lauric, and capric acids. 'I'he azelaic, pelargonic and shorter chain fatty acids are obtained in substantially 'equalv fractions; that is, one-third azelaic, one-l third pelargonic, and one-third shorter chain fatty acids. From the triglyceride of oleic acid, one obtains pelargonic acid and mixed glycerides of azelaic, palmitic, myristic, lauric, and capric acids. From the fatty acids of rape seed oil, one obtains pelargonic acid and brassylic acid in substantially equal quantities, and approximately the same amount-of a fraction consisting of satu. rated .fatty acids of shorter chain length than the fatty acids of rape seed oil. If esters. such as the methyl, ethyl, or propyl of an unsaturated fatty acid such as oleic are utilized as starting materials, the resulting products are pelargonic acid, the methyl, ethyl, or propyl half-ester of azelaic acid, and the shorter chain saturated fatty acids of the type described.` One method of separating these reaction products is described and claimed in our copending application Serial No. 433,516, now Patent 2,389,191.

According to this disclosure, the oxidation products of an oleic acid which are in admixture differ chemically from one another but do not diiler appreciably as to specific gravity and, in

ure, are quite homogenous. It has lbeen appreciated that some of the dibasic acids produced, like azelaic acid, are water` soluble and that water, therefore, is susceptible to use as an extracting medium, but such large quantities of water are required to dissolve the azelaic acid in the presence of the other components that the cost of separation is prohibitive.

We have discovered, however, that if the pel'ar- 'gonic acid (and similar acids resulting from the cleavage of the dowble bonds) Abe first reture, then the process of separation may be effected easily and economically by the use of an aqueous solvent in which one of the components is soluble but not both. More specifically, lwe have discovered that only limited quantities of such a solvent are required to effect the separation `of dibasic acids from the by-product acids when the pelargonic acid component is absent.

In the preferred practice of the invention, hot

'water is employedvas the solvent, extracting medium for separating the dibasic acid or acids -from by-product acids following the removal of the pelargonic acid which may be present.

In more detail, the process is as follows: It is desirable first to treat the commingled bodies produced from the oxidation process so as to remove whatever oxidizing agent may have been entrained therein. For example, the oxidation products are treated with concentrated-sulphuric acid whereby all organic chromic compounds are decomposed and the chromium removed as chromium sulphate dissolved in the acid layer. It is desirable to carry the oxidation process far enough to reduce the iodine value to as low a point as conveniently practical, `for example, say to 3. When this is done, substantially no unsaturated compounds remain and the products of oxidation can then be subjected to treatment by concentrated sulphuric acid without running the risk of forming sulphonated or sulphated fatty compounds. The formation of sulphonated products is undesirable because such materials may act as emulsifying agentsvmaking the following separation steps much more diilicult to perform.

It is desirable to remove as much as possible the sulphuric acid by washing they mixture with products of oxidation in admix-y small amounts of water. The use of large quantlties of Water for washing out the sulphuricV acid is to be avoided because the dibasic acids are soluble in the water and some, therefore, may be lost when the sulphuric acid is removed. The last traces of min'eral acidity are destroyed by neutralizing with a suitable alkali.

Having then a body consisting of dibasic, monobasic and by-product acids in the commingled state substantially free of oxidizing agent or sulphonation products, the pelargonic acid is the first to be removed. This is performed preferably by a topping distillation operation. The pelargonic acid is evaporated and the vapors condensed and isolated as the first product, leaving in liquid admixture the azelaic acid and whatever higher molecular weight monobasic acids may be present as by-products of the oxidation process, or whi-ch were initially present in the material being treated.

Upon removal of the pelargonic acid, the azelaic acid and commingled by-product acids are washed with hot Water a plurality of times. This step causes the azelaic acid to be dissolved in the wash water. The by-product acids are insoluble in the water and this step, therefore, enables the by-product acids to be separated and recovered by decanting.

While azelaic acid in admixture with by-product acids is soluble selectively when the mixture is washed with water, it is also to be observed that an aqueous solution of azelaic acid acts as a solvent for by-product acids if the concentration of azelaic acid in the Water solution becomes too high. lTo avoid such contamination the preferred method is to wash a given batch of the mixture being separated a number of times and controlling the total amount of thewater used in such manner that the azelaic acid content of the combined washes will not exceed approximately The first wash water may contain a percentage of i azelaic acid somewhat higher than 10%, the subsequent washes less. Clean, sharp separations are obtained when the concentration of azelaic acid in the collected wash waters does not exceed approximately 10%. Usually the total amount of wash water to be employed for treating a given batch which is being separated is divided in anywhere from three to six parts so that the mixture can be subjected to washing with from three to six batches of fresh wash water. It is to be noted that when the wash waters are collected and permitted to stand. an. additional amount of byproduct oil separates; this is due to the fact that when the first batch of wash Water is added the amount of azelaic acid which dissolves in it exceeds 10% and therefore carries some by-product acid into the ffirst wash water solution. The second and succeeding wash waters will contain amounts of azelaic acid less than 10%. When all wash waters are combined the total concentration of azelaic acid is sufficiently low that the azelaic acid cannot hold by-product acids in the solution. It is desirable to maintain the solution well above the crystallization point of azelaic acid during the settling period.

From this point on, two alternative procedures are available for recovering the azelaic acid from the wash water. In therst procedure, the azelaic acid is crystallized from the aqueous solution by chilling it to a point below the temperature of crystallization. In the other procedure, the water of the aqueous solution is removed by distillation, or evaporation.

The crystallization process is most suited for the production of crystals of azelaic acid of the highest purity but this process is the most expensive. Moreover, in the crystallization process a certain fraction of azelaic acid remains in the mother liquorafter crystallization is substantially completed. Because of cost it is requisite that the mother liquor from which azelaic crystals have been removed be used as wash water for the next successive batch. Such wash water, having a certain quota of azelaic acid already contained in it, has less solvent power for azelaic acid than distilled water, and greater quantities of water are required to keep below the 10% maximum. It is also to be noted that any impurities contained in such wash water are recycled. The removal of the water by evaporation or distillation is therefore preferred.

The details of typical separation procedure are as follows:

Two hundred and twenty-nine pounds of oxidized mixture of low iodine value are treated with 3% by weight of 60 B. suiphuric acid with agitation while heating to a temperature of to C. for one-half hour. The mixture is allowed to settle for about one-half hour and the separated sulphuric acid solution of chromium sulphate drawn off.

The oxidized mixture having been freed of its green coloration is washed twice with water using 6 pounds of Water for each wash and then l pound of caustic soda dissolved in alittle water is added.

This mixture with all mineral acidity neutralized is dried and distilled. The fraction obtained by heating up to 410 F. under 1% inches absolute pressure amounting to 91 pounds consists of pelargonic acid.

The still residue amounting to 138 pounds is agitated with 30 gallons of boiling water and allowed to settle. The lower aqueous solution is drawn olf. Three additional similar washings are made and the combined aqueous solutions are allowed t-o settle while hot. Any oil carried by the first washes is separated.

The clear azelaic acid solution is cooled to 70 F. in a crystallizing vessel with agitation. The azelaic acid slurry is then centrifuged to remove most of the water and the wet centrifuge cake dried in a suitable dryer. Approximately 60 pounds of azelaic acid are obtained.

The oily by-product residue remaining amounts to 70 pounds.

Other typical examples of the separation of the components in mixed oxidation products appear in the aforesaid copending patent application, Serial No. 433,516. v

The following examples are provided to assist the skilled of the art in the understanding of our process of oxidizing unsaturated fatty bodies.

Example I .--Ozidaton of oleic acid A spent solution of the following composition:

Percent Chromium sulphate ..-26.9 Sulphuric acid 12.2 Water 60.9

is fed into the cathode chambers of a series of continuous cells with lead electrodes and ceramic diaphragms of low electrical resistance and electrolyzed at 24 amperes per square foot anode current density. The solution flows from the cathodes to the anodes where it is electrolyzed to 50% conversion by controlling the rate of liquid feed. With an eicient cell about 1.8 k. w. h. per pound chromic acid can readily be obtained.

Commercial oleic acid, 3000 pounds, is treated in 3 treatments with a total oi' 62,040 pounds of the above 50% electrolyzed'solution flowing from the anodev chambers and having the following composition:

- Percent Chromic acid 6.77 Chromium sulphate 13.2 Sulphuric acid 21 Water 58.1

The reaction mixture is mechanically agitated and cooled to maintain a reaction temperature of 8090 C. When the reaction of the first treatment is completed as indicated by the pure vgreen color of the spent solution the mixture is. settled and the spent solution separated from the oxidized product. The product is again treated in the same manner with the other two parts of the above total solution respectively.

After the last treatment, the oxidized-product after suitable separation4 is foundto yield 1140 pounds of dibasic acids, chiefly azelaic acid. and

1200 pounds of low molecular weight monobasicl acids, chiefly pelargonic acid, and 700 pounds (approximately) of so-called by-product acids consisting of higher dibasic acids, vrrnonobasic acids, and oxidized acids. Example II.-0a:idation of cottonseed fatty acids Scl e Petroleum-ether soluble' material v(chiefly 100 parts o'f distilled cottonseed fatty acids asf sumed to consist of approximately oleic acid,

% linoleic acid, 20% palmiticl acid, and 5% of v Y tion,

other solid fatty acids are agitated in a suitablev 1 reaction vessel and treated with 8521.2 parts ofan oxidizing solution consisting of Percent version in a suitable, continuous, electrolytic cell a spent solution of the following composition:

- Percent Chromium sulphate 26.9 Sulphuric acid 12 9 Water 60.9

The temperature is not allowed to exceed approximately 90 C. by controlling therate of addition of oxidizing solution and by cooling the reaction vessel, if necessary.

After reaction is complete, the spent solution is drawn off and two additional similar treatments performed. The products of reaction'may be suitably separated to yield Percent Dibasic acids 2 Monobasic solid fatty acids (chiefly palmitic acid) Liquid monobasic fatty acids (chiefly pelarl gonic acid) 40.1 Based on the original fatty acids.

Example IIL- Oxidation of methyl oleate parts of methyl oleate contained in a lead or glass-lined reaction vessel equipped with cooling coils vare treated with 225.2'parts of an oxidizing solution consisting of Percent Chromic acid 6.77 Chromium sulphate '13.2 Sulphuric acid 21.9 Water 58.1

which is added fairly rapidly. The reaction is exothermic and the rateo! addition and cooling i 10 effect which can be obtained by passing cooling water through the coils is balanced so that the temperature does not rise over 90 C. After the reaction is complete, the spent solution is drawn oir and four additional similar treatments carried out. f

Th'e reaction products may be separated, yielding:

Percent A neutral low iodine value ester -15.6 Pelargonic acid 38.8 t Azelalc acid 40.0

Example IV.-Ozida ton of teaseed oil 100 parts teaseed oil are oxidized withl 601 parts of an oxidizing solution of thesamecompositionas inthe examples above. The temperature is '"rr5t"al1owed to exceed 90 C. by use of suitable coils in the reaction vessel and by control of the rate of addition of the oxidizing solution. When reaction is complete, the spent solution is drawn off and two other similar treatments carried out.

The products of reaction consist of:

Petroleum-ether insoluble material (chiefly azelaic acid triglyceride) 46.8

pelargonic acid) 60.7

Based onthe original fat.

Fromthe point of view of commercial operawhich involves the production of the active oxidizing agent at thelowest cost, we recommend the use of'thetype of continuous cell'with'lead electrodes-'described in .Example I, though, of

course, othertypes-of ,electrolyzing equipment f may be yused if desired.

. For the purpose koi' obtainingthe ,highestl possi-- bleyields of'dibasic' acids and also for thepurpose of avoiding fthe. presence of organic matter in the spent solutiontqbe electrolyzed, we recommend that the spent-'soiution and organicy materialbe f separatedf'at atemperature below 40 C., that is,

that the solution be cooled before being subjected to electrolysis. This may be done by permitting an admixture of the fatty material and the oxidizing solution to cool before separating them, or

the spent oxidizing solution may be removed from the main body of fatty material at reaction temperature, then cooled and preferably filtered to remove the organic material (primarily dibasic acids) dissolved by it at the higher temperature. By observing this technique, the yields are maintained at maximum and organic material is excluded from the electrolytic processes.

By our process, unsaturated fatty bodies are destructively oxidized to produce high yields of more valuable saturated fatty materials. There has long been a demand for relatively long chain dibasic acids to be used in themanufacture of resins, plasticizers', polymers, and like products. There also has been and is a large demand for hardened fats. The present invention provides a process by which water is electrolyzed to pro- 1. The method of oxidizing relatively long chain unsaturated fatty bodies to produce 1krela- Percent l,

tively short chain saturated fatty bodies, said method comprising electrolyzing an aqueous solution containing substantially 7 to 20% sulphuric acid and substantially 15 to 35% chromium sulphate to liberate hydrogen and convert 40 to 75% of chromium sulphate to chromic acid and sulphuric acid, treating the fatty body with said solution to produce cleavage of the chain and separating the fatty bodies so treated from said solution. all percentages being by weight.

2. The method of oxidizing relatively long chain unsaturated fatty bodies to produce relatively short chain saturated fatty bodies, said method comprising electrolyzing an aqueous solution containing substantially '7 to 20% sulphuric acid and substantially 15 to 35% chromium sulphate to liberate hydrogen and convert 40 to 75% of chromium sulphate to chromic acid and sulphuric acid, treating the fatty body with said solution at a temperature above 50 C. but below 100 C. to produce cleavage ofthe chain and separating the fatty bodies so treated from said solution at a temperature below 40 C., all percentages being by weight.

3. The method of oxidizing relatively longA chain unsaturated fatty bodies to produce relatively short chain saturated fatty bodies. said method comprising electrolyzing an aqueous solution containing substantially 7 to 20% sulphuric acid and substantially 15 to 35% chromium sulphate to liberate hydrogen and convert substantially 40 to 75% of chromium sulphate to chromic acid and sulphuric acid, treating the fatty body with said solution to produce cleavage of the chain, cooling said solution to precipitate the fatty bodies dissolved in it but not suficiently to precipitate chromium sulphate, and separating the fatty body so treated from said solution, all percentages being by weight.

4. The method of oxidizing relatively long chain unsaturated fatty bodies to produce relatively short chain saturated fatty bodies, sa-id method comprising electrolyzing an aqueous solution containing free sulphuric acid and chromium sulphate but less than 35% chromium sulphate by weight to liberate hydrogen and convert some but not all of the chromium sulphate to chrom-ic acid and sulphuric acid, treating the fatty body with said solution to produce cleavage of the chain, cooling said solution to precipitate dissolved fatty bodies, and separating the fatty body so treated from said solution.

5. The method of oxidizing relatively long chain unsaturated fatty bodies to produce relatively short chain saturated fatty bodies, said method comprising electrolyzing an aqueous solution containing free sulphuric acid and chromium sulphate but not over 35% chromium sulphate by weight to liberate hydrogen and convert some but not all of the chromium sulphate to chromic acid and sulphuric acid, treating the fatty body with said solution at a temperature above 50 C. and below 100 C. to produce cleavage of the chain and separating the fatty body so treated from said solution at a temperature below 40 C.

6. The method of oxidizing relatively long chain unsaturated fatty bodies to produce relatively short chain saturated fatty bodies, said method comprising electrolyzing an aqueous solution containing sulphuric acid and chromium sulphate to liberate hydrogen and convert chromium suiphate to chromic acid, treating the fatty body with said solution at a temperature above 50 C. and below 100 C., cooling said solution to produce cleavage of the chain to a degree which precipitates the fatty bodies dissolved in said solution without precipitating chromium sulphate, and

separating the fatty bodies from the solution.

7. The method of oxidizing relatively long chain unsaturated fatty bodies to produce relatively short chain saturated fatty bodies, said method comprising electrolyzing an aqueous solution containing substantially 7 to 20% sulphuric acid and substantially 15 to 35% chromium sulphate to liberate hydrogen and convert 50 to 60% of chromium sulphate to chromic acid and sulphuric a'cid, treating the fatty body with said solution to produce cleavage of the chain and-separating the fatty bodies so treated from said solution, all percentages being by weight.

8. The method of oxidizing relatively long chain unsaturated fatty bodies to produce relatively short chain saturated fatty bodies, said method comprising electrolyzing an aqueous solution containing substantially l0 to 15% sulphuric acid and substantially 15 to 35 chromium sulphate to liberate hydrogen and convert 40 to 75% of chromium sulphate to chromic acid and sulphuric acid, treating the fatty body with said solution to produce cleavage of the chain and separating the fatty bodies so treated from said solution, all percentages "being by weight.

9. The method of oxidizing relatively long chain unsaturated fatty bodies to produce relatively short chain saturated fatty bodies, said method comprizing electrolyzing an aqueous solution containing substantially 10 to 15% sulphuric acid and substantially 15 to 35% chromium sulphate to liberate hydrogen andv convert 50 to 60% of chromium sulphate to chromic acid and sulphuric acid, treat-ing the fatty body with said solution to produce cleavage of the chain and separating the fatty bodies so treated from said solution, all percentage being by weight.

10. The method of oxidizing relatively long chain unsaturated fatty bodies to produce relatively short chain saturated fatty bodies. said method comprising electrolyzing an aqueous solution containing over 7% sulphuric acid and substantially 15 to 35% chromium sulphate to liberate hydrogen and convert 40 to 75% of chromium sulphate to chromic acid and sulphuric acid, treating the fatty body with said solution to produce cleavage of the chain and separating the fatty bodies so treated from said solution, all percentages being by weight.

11. The method of oxidizing krelatively long chain unsaturated fatty bodies to produce relatively short chain saturated fatty bodies, said method comprising electrolyzing an aqueous solution containing over 7% sulphuric acid and substantially 15 to 35% chromium sulphate to liberate hydrogen and convert 40 to 75% of chromium sulphate to chromic acid and sulphuric acid all percentages being by weight, treating the fatty body with said solution to produce cleavage of the chain, separating the fatty bodies so treated from said solution, and filtering said solution at a temperature below 40 C. to remove fatty material from it.

12. The method of oxidizing relatively long chain unsaturated fatty bodies to produce relatively short chain saturated fatty bodies, said method comprising treating said relatively long chain unsaturated fatty bodies with an oxidizing solution comprising substantially 6.77% chromic acid, 13.2% chromium sulphate, 21.9% sulphuric acid and 51.8% water, all percentages beirfg by weight, to produce cleavage of the chain.

13. The method of oxidizing relatively long chain unsaturated-fatty bodies to produce relatively short chain saturated fatty bodies, said method comprising treating said relatively long chain unsaturated fatty bodies with an oxidizing solution comprising chromic acid, chromium su1- phate, sulphuric acid and water. to produce cleavage of the chain.

14. The method of oxidizing relatively long chain unsaturated fatty bodies to produce relatively short chain saturated fatty bodies, said method comprising treating said relatively long chain unsaturated fattybodies with an oxidizing solution to produce cleavage of the chain, said oxidizing solution being formed byelectrolyzing an 'aqueous solution containing substantially 7 to 20% sulphuric acid and substantially 15 to 35% chromium sulphate to liberate hydrogen and convert 40 to 75% of the chromium sulphate solution to produce cleavage of the chain, said oxidizing solution being formed by electrolyzing an aqueous solution containing `free sulphuric acid and chromium sulphate but not over 35% by weight of chromium sulphateto liberate hydrogen and convert some but not all of the chromium sulphate to chromic acid and sulphuric acid, said long chain unsaturated fatty bodies being treated with said solution at a temperature above 50 C. and belofw 100 C., and separating the fatty bodies so treated from said solution at a temperature below 40? C. o

19. The method of oxidizing relatively long chain unsaturated fatty bodies to produce relatively short chain saturated fatty bodies, said method comprising treating said relatively long s chain unsaturated fatty bodies with an oxidizing to chromic acid and sulphuric acid, and separating the fatty bodies so treated from said solution, all percentages being by weight,

15. The method of oxidizing relativelyv long chain unsaturated fatty bodies to produc'e rela'- tively short chain saturated fatty bodies, said' method comprising treating said relatively long chain unsaturated fatty bodies with an oxidizing "i solution to produce cleavage of the chain, said 1 oxidizing solution being formed by electrolyzing an aqueous solution containing substantially 7 to 20% sulphuric acid and substantially l5 to 35% chromium sulphate to liberate hydrogen and con-I vert 40 to 75% of the chromium sulphate lto chromic acid and sulphuric acid,l said relatively long chain unsaturated fatty bodies being treated with said solution at a temperature above 50 C.

but 'below 100 C. and separating the'fatty bodies so treated from said solution at a temperature below 10 C., all percentages being by iweight.

16. The method of oxidizing relatively long chain unsaturated fatty bodies to produce relatively short chain saturated said solution to precipitate the fatty bodies dissolved in it but not sufficiently to precipitate chromium sulphate, and separating the fatty body so treated from said solution, all percentages being by weight. y

17. The method of oxidizing relatively long chain unsaturated fatty bodies to produce relatively short chain saturated chain unsaturated fatty bodies with an oxidizing solution to produce cleavage of the chain. said oxidizing solution being formed by electrolyzing an aqueous solution containing `free sulphuric acid and chromium sulphate but less than 35% by weight of chromium sul-phate to liberate hydrogen and convert some but not all of the chromium sulphate to chromic acid and sulphuric acid, cooling said solution to precipitate dissolved fatty bodies. and separating the fatty bodies so treated from said solution. y

18. The method of oxidizing relatively long chain unsaturated fatty bodies to produce relatively short cbain saturatedfatty bodies4 said method comprising treating said relatively long chain unsaturated fatty bodieswlth anoxidizing fatty bodies, saidv methodcomprising treating said relatively long fatty bodies, saidmethod comprising treating said relatively long solution to produce cleavage of the chain, said oxidizing solution being formed by electrolyzing an aqueous solution containing sulphuric acid and chromium sulphate to liberate hydrogen and convert chromium sulphate to chromic acid, said fatty body being treated with said solution at a temperature above 50 C. and below 100 C., coolingsaid solution to a degree which precipitates the'fattybodies dissolved in said solution without precipitating chromium'sulphate, the fatty bodies from the solution.

20. ThefmethodA of oxidizing relatively long chainunsaturated fatty bodies to produce relatively short chain saturated fatty bodies, said method comprising treating said relatively long chain unsaturated fatty bodies with an oxidizing solution to produce cleavage of the chain, said oxidizing solution being formed by electrolyzing an aqueous solution containing substantially 7 to 20% sulphuric acid and substantially 15 to 35% chromium sulphate to liberate hydrogen and convert 50 to 60% of the chromium sulphate to chromic acid and sulphuric acid, and separating the fatty bodies so treated from said solution, all percentages being by weight.

21. The method of oxidizing relatively long chain unsaturated fatty bodies to produce relatively short chain saturated fatty bodies, said method comprising treating said relatively long chain unsaturatedfatty bodies with an oxidizing solution to produce cleavage of the chain. said oxidizing solution being formed by electrolyzing an aqueous solution containing substantially 10 to 15% sulphuric acid and substantially 15 to 35% chromium sulphate to liberate hydrogen and convert 40 to 75% of the chromium sulphate to chromic acid and sulphuric acid, and separating the fatty bodies so treated from said solution, all percentages being' by weight.

22. The method of oxidizing relatively long chain unsaturated fatty bodies to produce relatively 'short chain saturated fatty bodies, said method comprising treating said relatively long chain unsaturated fatty bodies with an oxidizing solution to produce cleavage of the chain. said and separating oxidizing solution being formed by electrolyzing vert 50 to 60% of the chromium sulphate to chromic acid and sulphuric acid. and separating the fatty bodies so treated'from said solution, all percentages being by weight.

23. The method of oxidizing relatively long chain unsaturated fatty bodies to produce relatively short chain unsaturated fatty bodies, said method comprising treating said relatively long chain unsaturated fatty bodies with an oxidizing solution to produce cleavage ot the chain, said oxidizing solution being formed by electrolyzing an aqueous solution containing over '7% sulphuric acid and substantially 15 to 35% chromium sulphate to liberate hydrogen and convert 40 to '15% 5 of the chromium sulphate to chromi'c acid and sulphuric acid, and separating the iatty bodies so treated from said solution, all percentages be.. ing by weight.

24. The method of oxidizing relatively lon'g 10 chain unsaturated fatty bodies to produce relatively short chain saturated fatty bodies, said method comprising treating said relatively long chain unsaturated fatty bodies with an oxidizing soli-tion to produce cleavage of the chain, said 15 oxidizing solution being formed by electrolyzing an aqueous solution containing over 7% sulphuric 16 acid and substantially 15 to 35% chromium sulphate to liberate hydrogen and convert 40 to 75% of the chromium sulphate to chromic acid and REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Name Date Number Hervey Nov. 7. 1939/ 

